Deep Exploration Technologies CRC: Uncovering the Future

1. Deep Exploration Technologies CRC: Uncovering the Future David Giles Program 3 Leader DET CRC School of Earth and Environmental Sciences The University of Adelaide Prospecting at Depth What compromises are you willing to make?

2. Thesis • We don’t understand complex mineral systems nearly as well as we think we do • You can’t predict the unpredictable • You can only map and sample the systems at a detail appropriate to the system and to your needs • Where prospective rocks are exposed this process is called ‘prospecting’ • Prospecting can be very effective – low cost – drives and informs the exploration cycle – mitigates risk • Where prospective rocks are covered we don’t yet have an equivalent • Increased sample density requires reduced cost per sample • What compromises are acceptable? • DET CRC research aims to address this issue

3. Ore deposits (and associated fault networks) tend to have a fractal distribution. Scale independent distribution at the length scales appropriate to exploration.

4. Ore deposits tend to have a fractal distribution Scale independent distribution at the length scales appropriate to exploration

5. From: Seismicity parameters of Seismogenic Zones (AviShapira and Abraham Hofstetter) www.gii.co.il/heb/ Teken/seismicity-rprt.htm Global porphyry deposits (234) Size vs frequency gives straight line in log-log Self Organized Critical Systems Inherently unpredictable Dead sea rift earthquakes

6. This analogy does not sound very encouraging to a mineral explorer. Because we have to do more than find the fault – we have to effectively predict the earthquake. However there are a number of reasons for us to be encouraged: 1. We can employ methods of pattern recognition informed by experience (geologists intuition), for example…

7. Ore deposits are distributed in clusters both in space…

8. …and in time…

9. Hodkiewicz et al, 2005, AJES 52: 831-841 …and are focused in zones of structural complexity

10. There are a number of reasons for us to be encouraged: 2. We don’t have to predict into the future. We are making a spatial prediction on past events and as such WE DON’T HAVE TO PREDICT WE CAN OBSERVE and MEASURE in order to build a picture of the PATTERN. IN GEOLOGY WE CALL THAT MAPPING and SAMPLING

11. 400km 200km Semi-regular sampling at 80km intervals shale granite siltstone basalt limestone sandstone

12. 400km 200km Semi-regular sampling at 40km intervals shale granite siltstone basalt limestone sandstone

13. 400km 200km Semi-regular sampling at 20km intervals shale granite siltstone basalt limestone sandstone

14. 400km 200km Semi-regular sampling at 10km intervals shale granite siltstone basalt limestone sandstone

15. 400km 200km Semi-regular sampling at 5km intervals shale granite siltstone basalt limestone sandstone

16. 400km 200km The full complexity revealed!

17. There are a number of reasons for us to be encouraged: 3. We can use our understanding of mineral systems and secondary dispersion processes to markedly increase the size of the target FOOTPRINT. (the analogy is identifying the epicentre of an earthquake by measuring the intensity of damage at the surface)

18. In deposit sampling we are interested in constraining the distribution of grade and mineralogy (deleterious materials, mining parameters…) at a scale appropriate to mining (~5m). In exploration sampling we are interested in any rock property (geochemistry, mineralogy, texture, petrophysics) that will allow us to reconstruct the mineral system (ie recognise the pattern) at a scale that will allow us to make the next targeting decision.

19. murphygeological.com Alunite alteration associated with high sulphidation epithermal systems in northern Chile 5km

20. www.magellanminerals.com

21. PROSPECTING Why we love it… • Low cost • Maps system • Informs decisions • Drives progress through exploration cycle www.orezone.com

22. At depth no prospecting phase! • Fabulous large scale datasets but… • Often single data set anomaly • Deep hole – high cost – big risk – long lead time to validation • Lots of false positives

23. Prospecting at depth At present we have sparse sampling coupled with regional geophysical data (mostly potential fields) Geophysics lends itself to structural interpretation (equivalent of identifying the fault corridor for earthquake prediction). But huge ambiguity about detail of structures, rock types, alteration, elemental geochemistry (particularly if these variables do not influence the geophysical signature). The only way to overcome this ambiguity is to sample.

24. The only way to sample is to drill The only relevant questions relate to our drill sampling strategy: Which drilling method, how many samples, what spacing, what materials, what elements, what detection limits? Can we achieve such a strategy in an efficient and cost competitive way at best practice OHS and environmental standards. This is the business of the DET CRC

25. Compromise is necessary! The ideal: Representative, reproducible, accurately located, no contamination, broadest suite of analyses at lowest detection limits, textural data, rapid acquisition, rapid analyses, cost effective SAMPLE QUALITY vsSAMPLE DENSITY

26. Elements of the Plan A new paradigm for drilling Real time quantitative data capture Decision making tools All Underpinned by knowledge of the host rocks and mineral system!

27. PROGRAM 1: Drilling Technologies • ~1,000m Alberta gas wells with 4.5” casing • 2-3 hours move in and rig up time • 2 wells/day achieved • $US 8,000 per well for drilling • improved cost, safety, environmental impact and hole stability in minex • key challenges for minex include: coil durability, low WOB drilling • initial target: • greenfields rig to 500m, less than 5 tonnes and $50/m

28. Coiled Tube drilling for MinEx Advantages Cheap and rapid drilling Light, small footprint – access and enviro Rapid mobilisation No drill rods – OHSE Sample is pulverised and homogeneous Challenges Accurate location of drill bit (sample) Depth fidelity and contamination Can it be done?

29. Program 2: Logging and Sensing Fe content PGNAA Bore Hole Radar

30. Downhole Sensing Advantages Real time, at site analyses Single deployment – while you drill Most wireline techniques applicable without significant compromise on data quality Geophysical logging Challenges Down hole environment challenging for geochem and mineralogy What do you do with all the data?

31. Program 3 Deep Targeting Hematite 10x vertical exaggeration Magnetite Hematite – Magnetite Emmie Bluff Albite K-Feldspar Sericite Sericite – Chlorite Chlorite 2 km 500 m x 500 m x 10 m cell size Emmie Bluff 3D Model Alteration voxet N 10 km 10 km

32. Top hole Sensing Advantages Real time, at site analyses Single deployment – immediately following drilling Existing techniques for geochem and mineralogy (eg. pXRF/XRD and hyperspectral scanners) Challenges Sample quality depends on drilling and sampling techniques (Program 1) Compromise on detection limits…

33. Scale of footprint depends on sampling and analytical methodology! (Image from S. Halley) Detection limit critical for single element footprint

34. However for pattern recognition at scales appropriate to exploration multiple streams of lesser quality but higher density data, delivered in real time to inform decision making are extremely useful…

35. Portable XRF – analyses as quick as you can dril Can you see the pattern?

37. Current Practice • IOCGs, Gawler Craton, SA • drill through deep cover based on grav & mag anomalies alone • many false +ves • many anomalies tested by one hole • sparse data collected with little knowledge to inform follow-up drilling Source: Simon van der Wielen

38. Olympic Domain DET CRC Deep Prospecting Strategy Identify target based on geophysics and prior drilling Subtle feature in regional gravity survey Image courtesy of Simon van der Wielen

39. 9 holes ~400m $50/m =$180K Olympic Domain DET CRC Deep Prospecting Strategy Systematically sample target area with cheap, rapid drilling + real time analyses Hole on gravity high ‘fails’ but pathfinder geochemistry in all holes hints at a broader pattern and informs follow up drilling 5km grid pattern Pathfinder element X Anomaly Background

40. 56 holes =$1,120K Olympic Domain DET CRC Deep Prospecting Strategy Prioritise follow up drilling on-the-fly Expand drill pattern and chase geochemical gradients toward the east and north Identify alteration footprint 5km grid pattern ‘failed’ initial target Pathfinder element X Anomaly Background

41. 89 holes =$1,780K Olympic Domain DET CRC Deep Prospecting Strategy Prioritise infill drilling on-the-fly Identify hot-spots within the footprint for deep targeting with high level of confidence 5km grid pattern ‘failed’ initial target Pathfinder element X Anomaly Background

42. Olympic Domain DET CRC Deep Prospecting Strategy Expanded regional survey identifies new target zones for infill and follow-up drilling Begin to map the mineralising system Targets based on broad bandwidth of data reduces false +ves and allows recognition of new deposit styles Pathfinder element X Anomaly Background